4. In this cartoon-like simulation we illustrate how a polaron moves through a 1-dimensional lattice. A polaron is a quasi-particle formed of a charge plus a local distortion that follows it; this distortion may extend several atomic spacings from the charge. The top figure shows the static distortions in the vicinity of a polaron while the movie shows the changes in the local atomic environment as the polaron moves through the lattice. Note that these atomic displacements are electronically driven - they are not thermal phonons. The changes in σ can be quite large.